Connector for flat multiconductor cables

ABSTRACT

A connector for use with multiple conductor flat cables is disclosed which contains two clamp blocks, a center block and a number of contact members. The clamp blocks are positioned on either side of the center block and the contact members are located within the body of the center block.

United States Patent inventor Joseph M. Niedzwiecki Brick Town, N.J.

Appl. No. 881,064

Filed Dec. 1, 1969 Patented Oct. 12, 1971 Assignee Bell Telephone Laboratories, Incorporated Murray Hill, Berkeley Heights, NJ.

CONNECTOR FOR FLAT MULTICONDUCTOR CABLES 8 Claims, 7 Drawing Figs.

U.S. Cl 339/92 M, 339/176 MF, 339/278 C Int. Cl H0lr 13/54 Field of Search 339/17, 75, 92, 176, 278

[56] References Cited UNITED STATES PATENTS 2,846,649 8/1958 Hornauer 324/155 3,307,139 2/1967 Prise i. 339/176 MF 3,329,926 7/1967 Aksu et a1. 339/176 MP Primary Examiner-Joseph H. McGlynn Attorneys-R. J. Guenther and Edwin B. Cave ABSTRACT: A connector for use with multiple conductor flat cables is disclosed which contains two clamp blocks, a center block and a number of contact members. The clarrp blocks are positioned on either side of the center block and the contact members are located within the body of the center block.

PATENTEBUET 12 1971 SHEET 10F 2 FIG! @v. x \s INVENTOR M N/EDZW/ECK/ A T TORNEV PATENTED UET 12 IQ'II SHEET 2 OF 2 FIG. 6

CONNECTOR FOR FLAT MULTICONDUCTOR CABLES BACKGROUND OF THE INVENTION 1. Field of the Invention This invention pertains to connectors for multiconductor cables and relates particularly to conductors for use with cables which are flat and flexible.

2. Description of the Prior Art Conventional multiconductor cables having round cross sections are not suitable for all wiring applications. For example, where space is at a premium, the bulk and stiffness of a round cable is often unacceptable. Consequently, new cable forms have proliferated in which the conductors are aligned side by side to form a flat and flexible assembly. The new flat cables, however, are generally not compatible with old-style connectors. Consequently, flat cable connectors have been developed to provide a way of connecting flat cables to each other or to other appropriate electrically conducting apparatus.

The demand for flat cable connectors is large and growing. Since small savings in making individual connectors will multiply into large savings when making many connectors, the increasing demand for connectors in large numbers requires a design which will keep manufacturing costs to a minimum. Moreover, it is essential that each connector be simple to use and that it make and retain good electrical connection so that installation and maintenance costs can be kept at reasonable levels. It is imperative, therefore, that flat cable connectors be available which are simple to use, inexpensive to make and reliable in operation.

Accordingly, the object of this invention is to achieve reliability, simplicity for use, and low cost in the manufacture and application of flat cable connectors.

SUMMARY OF THE INVENTION In a preferred embodiment of this invention, two clamp blocks are disposed on either side of a center block. The two clamp blocks and the center block have facing bearing surfaces and the bearing surfaces cooperate to form two recesses suitable for accommodating cables to be joined. Electrical paths are extended between cables clamped in the two recesses by a group of contact members in which each contact member is made from a single, unitary piece of wire, has an end section projecting into each recess and is held in place by a center section which passes through the middle of the center block.

According to one feature of this invention, combining all of the connector elements into three basic parts simplifies connector usage.

According to another feature of this invention, locating each contact member within the body of the center block improves reliability by protecting the contact members from accidental damage attributable to causes arising outside the connector.

According to another feature of this invention, each contact member is made from a single unitary wire so that savings in manufacturing costs can be achieved by plating each contact member before it is inserted into the body of the center block.

DESCRIPTION OF THE DRAWING FIG. 1 is an exploded view taken in perspective, showing the location of a typical flat cable with respect to the center block and the two clamp blocks in a flat cable connector constructed in accordance with this invention;

FIG. 2 is an exploded end elevation of the parts shown in FIG. 1 with the addition of a second flat cable and illustrates the relationship of the parts of the flat cable connector in respect to each other;

FIG. 3 is an end elevation view taken in section showing an assembled flat cable connector electrically joining two flat cables;

FIG. 4 is an end elevation view of the components shown in FIG. 3, except that one flat cable has been replaced with a series of fixed contact members located in one of the clamp blocks;

FIG. 5 is a side elevation view of a flat cable connector made in accordance with this invention;

FIG. 6 is a section view taken along lines 6--6 of FIG. 5 illustrating a second form of contact member; and

FIG. 7 is a plan view of the connector member shown in FIG. 6.

DETAILED DESCRIPTION Referring to FIG. 1, a flat cable connector 10 is illustrated which comprises three basic parts, viz: two clamp blocks 11 and I2 and a center block 13. In typical use, the two clamp blocks 11 and 12, as illustrated in FIG. 3, cooperate with the center block 13 to electrically join a pair of flat cables 14.

As best seen in FIGS. 1 and 2, each flat cable 14 ends in a number of exposed conductors 15. In order to make a connection, the exposed conductors 15 are forced against corresponding contact members 16 which extend between the two cables. In the embodiment shown in FIGS. 1, 2 and 3, cooperating bearing surfaces 18 and 19 press the conductors 15 against the contact members 16. As best seen in FIG. 2, the bearing surfaces 18 are located on the clamp blocks 11 and 12, while the bearing surfaces 19 are located on opposite sides of the center block 13.

The two clamp blocks 11 and 12 are essentially alike, so a description of one will suffice for the other. As shown in FIGS. 1 and 2, the clamp block 12 is substantially rectangular in form and contains a groove 20 and a pair of guide pins 21 (only one shown) adjacent to the groove 20. As illustrated in FIG. 2, the bearing surfaces 18 are located on opposite walls of the groove 20. The clamp block 11 is conveniently made of an insulating plastic material such as diallyl phthalate and includes an arrangement by which it can squeeze the center block 13 against the clamp block 12. For example, as shown in FIG. I, the clamp block 11 may conveniently contain a pair of holes 22 suitable to accommodate a pair of bolts 23a and nuts 23b.

The center block 13, as best seen in FIG. 1, is substantially rectangular in shape. It is conveniently made of an insulating plastic material such as diallyl phthalate. As can be seen from FIGS. 1 and 2, the bearing surfaces 19 are interrupted by a number of slots 24. The slots 24, in turn, are interconnected by a number of holes 25. The number of slots 24 is determined by the nature of the cables to be joined. In the embodiment illustrated in FIGS. 1 and 2, a IO-conductor cable is contemplated. Consequently, l0 slots 24 appear in the center block 13.

The slots 24 are divided into two equal groups located on opposite sides of the center block 13. As shown in FIGS. 1 and 2, each is shorter than the full width of the side of the center block 13 and stops short of the edge to form a shoulder. As illustrated in FIG. 2, the holes 25 begin just in front of the shoulder.

As can be seen from FIG. I, each hole 25 accommodates one contact member 16. Each contact member 16 is made from a single piece of wire such as gold plated phosphor bronze or beryllium copper, and, as illustrated in FIGS. 2 and 3, is bent into an S-shape so as to have end sections projecting above the bearing surfaces 19. Because the contact members 16 pass through the middle of the center block 13, the S-shape is formed after insertion in the holes 25. Since final forming takes place after insertion in the center block 13, each contact member 16 can be made merely by inserting the end of a length of preplated wire into a hole 25 and clipping off the required segment. Alternatively, the contact members 16 can be molded into the center block 13. Using either technique, reductions in manufacturing costs are readily achieved.

In joining two flat cables 14, the cables are first positioned on the guide pins 21 on the clamp blocks 11 and 12. In the drawing, the mounting or guide holes in the cables which correspond to the guide pins 21 have not been shown. They are,

however, merely apertures which pass through the insulating material of the cables near the conductors 15.

Next, the center block 13 is placed between the cables and clamp blocks. As can best be understood from FIGS. 2 and 3, two cable-accommodating spaces or recesses are fomied between the bearing surfaces 18 and 19 as they approach each other.

Lastly, the clamp blocks 11 and 12 are drawn together against the center block 13 by, for example, driving the bolts 23a into the nuts 23b. As the clamp blocks 11 and 12 squeeze against the center block 13, the cables 14 are pressed into the grooves 20 and around the center block 13. As the cables 14 conform to the contour of the center block 13, the conductors 15 are pressed against the contact members 16, thereby establishing an electrical connection between the conductors in the two cables.

In the completed connector, contact pressure is readily adjustable without damage to the cables. As can be seen from FIG. 3, the ends of the contact members 16 project into the spaces or recesses between the bearing surfaces 18 and 19. Moreover, the surfaces of the conductors 15 are approximately level with the outer surfaces of the cables 14. Consequently, engagement of the contact members 16 and the conductors 15 occurs before the bearing surfaces 18 and 19 materially deform the insulating material of the cable 14. Moreover, the S configuration of the contact members 16 permits the amount of contact force to be adjusted simply by increasing or decreasing the squeezing force exerted by the clamp blocks 11 and 12. Thus, good electrical contact of readily adjustable magnitude is readily achieved in a simple manner without detriment to the cables 14.

In addition, the points of electrical contact between the conductors l and the contact members 16 are protected. When, as shown in FIG. 3, the clamp blocks 11 and 12 are clamped in the cable connecting position, the contact members 16 and the exposed conductors 15 are contained entirely within a protective housing. Consequently, all essential parts of the connector are protected from external injury.

Furthermore, cable disconnection and reconnection is quick and easy. To disconnect, the clamp blocks 11 and 12 are merely separated and the cables 14 removed from the guide pins 21. To reconnect, the cables 14 are placed back on the guide pins 21 and the clamp blocks 11 and 12 are again drawn together to force the conductors 15 against the contact members 16.

Alternatively, the use of S-shaped contact members facilitates connection between cables and other electrical apparatus. As shown in FIG. 4, a number of fixed contacts 27 are embedded in one of the clamp blocks 11 and 12. Each fixed contact 27 is made of a gold-plated material such as phosphor bronze, beryllium copper or brass, and is located so as to be in register with a contact member 16 when the clamp blocks 11 and 12 are positioned against the center block 13. Thus, when a cable 14 is clamped in place, electrical paths will extend from the conductors 15 to apparatus, terminated on the fixed contacts 27.

if desired, contact reliability can be further improved by modifying the form of the contact members and the center block. As shown in FIGS. 6 and 7, the contact members 16a are alternatively formed in an X configuration. As before, each is made of a single piece of wire such as phosphor bronze or beryllium copper and is preplated with a suitable contact material such as gold before assembly in the center block 13a. The four legs of each contact member 16a terminate in four contact points 31; two being closed and two being open hooks.

in order to accommodate the X-shaped contact members 16a, the slots 24a pass entirely through the center block 13a. Moreover, as shown in FIG. 6, they taper down to form midpoint shoulders 32 before flaring out again.

To insert a contact member 16a into the center block 13a,

the hook ends are squeezed together and pushed into a slot 244. After insertion, the contact member springs back to its original shape, but is engaged at its center by the shoulders As can be seen from FIGS. 5 and 6, the contact points 31 project upwardly from the center block 13a in order to engage the conductors 15 in the cables 14 in response to pressure exerted by the clamp blocks 11a and 120. Moreover, contact is made serially at two points on each conductor 15. Consequently, the possibility of a bad connection between a contact member 16a and a cable conductor 15 is cut in half, thereby insuring improved contact reliability.

In summary, a connector for use with multiple conductor flat cables has been disclosed which is reliable in application, simple to make and easy to use. It is to be understood that the embodiments disclosed merely exemplify the principles of the invention and many other embodiments falling within the spirit and scope of the invention will readily occur to others skilled in the art.

lclaim:

l. A connector adapted for use with multiple conductor cables comprising facing outer bearing surfaces located on two clamp blocks disposed in register with each other, inner bearing surfaces located on a center block in facing relationship to said outer bearing surfaces to fonn two conductor-accommodating recesses, contact members for extending electrical paths from one recess to the other, and means for urging said clamp blocks towards said center block to compress conductors located in said recesses against said contact members, CHARACTERIZED IN THAT each contact member is a unitary wire extending internally through said center block, has deflectable sections located in each recess for engaging conductors pressed between said inner and outer bearing surfaces, and has an intermediate section bearing against a solid interior portion of said center block whereby electrical contact is readily made between conductors located in opposite recesses.

2. A connector in accordance with claim 1 wherein each of said contact members has an S-shaped configuration.

3. A connector in accordance with claim 2 wherein said deflectable sections are located at the opposite ends of each connector member and extend into said recesses to exert a pretensioned force against conductors clamped between said inner and outer bearing surfaces.

4. A connector in accordance with claim 2 wherein one of said clamp blocks also includes a number of fixed contacts disposed in a row and said contact members are aligned in register with said fixed contact members so as to engage said fixed contact members when said inner and outer bearing surfaces are urged together.

5. A connector for flat cables comprising two clamp blocks disposed on opposite sides of a center block, said clamp blocks and said center block having bearing surfaces located in facing relationship to each other to fonn a pair of cable-accommodating recesses and said center block including a group of contact members in which each contact member has an X- shaped configuration, is made from a single unitary piece of wire, has an end section projecting into each of said recesses and includes a center section passing through the interior of said center block.

6. A connector in accordance with claim 5 wherein each contact member is made from a piece of preplated wire.

7. A connector in accordance with claim 5 wherein the midpoint of each contact member is located in the center of said center block and the ends of said contact member extend above the surface of said center block to form a pair of serially aligned contact surfaces in each recess.

8. A connector in accordance with claim 7 wherein at least two of said ends have hook-shaped deflectable sections projecting into said recesses. 

1. A connector adapted for use with multiple conductor cables comprising facing outer bearing surfaces located on two clamp blocks disposed in register with each other, inner bearing surfaces located on a center block in facing relationship to said outer bearing surfaces to form two conductor-accommodating recesses, contact members for extending electrical paths from one recess to the other, and means for urging said clamp blocks towards said center block to compress conductors located in said recesses against said contact members, CHARACTERIZED IN THAT each contact member is a unitary wire extending internally through said center block, has deflectable sections located in each recess for engaging conductors pressed between said inner and outer bearing surfaces, and has an intermediate section bearing against a solid interior portion of said center block whereby electrical contact is readily made between conductors located in opposite recesses.
 2. A connector in accordance with claim 1 wherein each of said contact members has an S-shaped configuration.
 3. A connector in accordance with claim 2 wherein said deflectable sections are located at the opposite ends of each connector member and extend into said recesses to exert a pretensioned force against conductors clamped between said inner and outer bearing surfaces.
 4. A connector in accordance with claim 2 wherein one of said clamp blocks also includes a number of fixed contacts disposed in a row and said contact members are aligned in register with said fixed contact members so as to engage said fixed contact members when said inner and outer bearing surfaces are urged together.
 5. A connector for flat cables comprising two clamp blocks disposed on opposite sides of a center block, said clamp blocks and said center block having bearing surfaces located in facing relationship to each other to form a pair of cable-accommodating recesses and said center block including a group of contact members in which each contact member has an X-shaped configuration, is made from a single unitary piece of wire, has an end section projecting into each of said recesses and includes a center section passing through the interior of said center block.
 6. A connector in accordance with claim 5 wherein eacH contact member is made from a piece of preplated wire.
 7. A connector in accordance with claim 5 wherein the midpoint of each contact member is located in the center of said center block and the ends of said contact member extend above the surface of said center block to form a pair of serially aligned contact surfaces in each recess.
 8. A connector in accordance with claim 7 wherein at least two of said ends have hook-shaped deflectable sections projecting into said recesses. 